3Examining the installation siteThe firewall can only be used indoors. To make sure the firewall operates correctly and to prolong itsservice lifetime, the installation site must meet the following requirements.Weight supportMake sure the floor can support the total weight of the rack, chassis, modules, and all othercomponents. For more information, see "Dimensions and weights."Temperature and humidityMaintain appropriate temperature and humidity in the equipment room.• Lasting high relative humidity can cause poor insulation, electricity leakage, mechanicalproperty change of materials, and metal corrosion.• Lasting low relative humidity can cause washer contraction and ESD and bring problemsincluding loose captive screws and circuit failure.• High temperature can accelerate the aging of insulation materials and significantly lower thereliability and lifespan of the firewall.For the temperature and humidity requirements of the firewall, see Table 2.Table 2 Temperature/humidity requirementsTemperature Relative humidity• Operating:{ Without hard disks: 0°C to 45°C(32°F to 113°F){ With hard disks: 5°C to 40°C(41°F to 104°F)• Storage: –40°C to +70°C (–40°F to+158°F)• Operating:{ Without hard disks: 5% RH to 95% RH, noncondensing{ With hard disks: 10% RH to 80% RH, noncondensing• Storage:{ Without hard disks: 5% RH to 95% RH, noncondensing{ With hard disks: 5% RH to 90% RH, noncondensingCleanlinessDust buildup on the chassis might result in electrostatic adsorption, which causes poor contact ofmetal components and contact points, especially when indoor relative humidity is low. In the worstcase, electrostatic adsorption can cause communication failure.Table 3 Dust concentration limit in the equipment roomSubstance Concentration limit (particles/m3)Dust particles ≤ 3 × 104(No visible dust on desk in three days)NOTE:Dust particle diameter ≥ 5 μmThe equipment room must also meet strict limits on salts, acids, and sulfides to eliminate corrosionand premature aging of components, as shown in Table 4.